Spring Shims - 1.250 OD .030 Thick

PAC Racing Springs Spring Shims in 1.250 OD .030 thick steel construction provide precise valve spring height adjustment for engine builders and performance engine tuners. These valve spring shims are engineered to maintain consistent spring preload and valve train geometry when stacking underneath valve springs, a critical requirement for any engine where OEM spring installed heights don't match performance camshaft specifications or where component tolerances require compensation.

Each shim features a 1.250-inch outer diameter with 0.570-inch inner diameter bore and 0.030-inch thickness, dimensions that work across a wide range of small-block and big-block applications. The steel construction resists deformation under the constant cyclic loads imposed by valve spring pressure, ensuring the height adjustment remains stable across thousands of engine cycles. This set includes 16 shims, providing the quantity needed for multiple cylinders or allowing engine builders to test different stack combinations before final assembly.

Professional engine builders rely on valve spring shims when installing performance camshafts with different lobe lift characteristics than factory specifications, when converting between valve spring styles, or when precision machining reveals that installed heights fall outside acceptable tolerances. Incorrect installed height reduces spring load at maximum lift, compromising valve control and risking float; shims provide a repeatable method to achieve exact specifications without replacing entire spring assemblies. PAC Racing Springs shims are recognized in circle track racing, street performance, and restoration builds as a standard solution for valve train optimization.